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posted by Fnord666 on Monday November 05 2018, @02:29PM   Printer-friendly
from the it-means-it's-composite dept.

Submitted via IRC for Bytram

What Is an "Almost Prime" Number?

When I saw a math paper with the phrase "almost prime" in the title, I thought it sounded pretty funny. It reminded me of the joke about how you can't be a little bit pregnant. On further thought, though, it seems like someone whose pregnancy is 6 weeks along and who hasn't yet noticed a missed period is meaningfully less pregnant that someone rounding the bend at 39 weeks who can balance a dinner plate on their belly. Perhaps "almost prime" could make sense too.

A number is prime if its only factors are 1 and itself. By convention, the number 1 is not considered to be prime, so the primes start 2, 3, 5, 7, 11, and so on. Hence, a prime number has one prime factor. A number with two prime factors, like 4 (where the two factors are both 2) or 6 (2×3) is definitely less prime than a prime number, but it kind of seems more prime than 8 or 30, both of which have three prime factors (2×2×2 and 2×3×5, respectively). The notion of almost primes is a way of quantifying how close a number is to being prime.


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  • (Score: 0) by Anonymous Coward on Monday November 05 2018, @04:01PM (7 children)

    by Anonymous Coward on Monday November 05 2018, @04:01PM (#758017)

    Pregnant is a simple yes/no field. Time elapsed within pregnancy is a separate value entirely. It should be a NULL value if the Pregnant field is set to NO, but I suppose there could be edge cases where that doesn't entirely hold true. Regardless though, they aren't the same thing - so good data hygiene practices should cause you to track them separately rather than overloading the definition of the one field.

    Honestly, mathematicians and their sloppy data management. Hrmph.

  • (Score: 3, Insightful) by Anonymous Coward on Monday November 05 2018, @04:27PM (2 children)

    by Anonymous Coward on Monday November 05 2018, @04:27PM (#758031)

    pregnant is not a yes/no field.
    you can have sex now, not be pregnant for a few hours, and then be pregnant for the following 9 months.
    or you can be pregnant for a few weeks and then not be pregnant again, and never actually realize you were pregnant (apparently this is quite common).

    it depends on the definition of "pregnant", plus the probability of sperm to fertilize egg, plus probability of fertilized egg to travel to the proper place, etc.

    • (Score: 0) by Anonymous Coward on Monday November 05 2018, @05:22PM

      by Anonymous Coward on Monday November 05 2018, @05:22PM (#758068)

      pregnant is not a yes/no field.
      you can have sex now, not be pregnant for a few hours, and then be pregnant for the following 9 months.

      Pregnant is a yes/no field. How and when preconditions occurred is not relevant to evaluating the current state of pregnancy. If you're going to argue that when sex was had determines current state of pregnancy, you might as well argue that a near-future miscarriage means that that a person isn't pregnant now.

    • (Score: 0) by Anonymous Coward on Monday November 05 2018, @10:18PM

      by Anonymous Coward on Monday November 05 2018, @10:18PM (#758222)

      Slashdot: where idiots argue over what it means to be pregnant.

  • (Score: 0) by Anonymous Coward on Monday November 05 2018, @04:56PM (2 children)

    by Anonymous Coward on Monday November 05 2018, @04:56PM (#758055)

    You'd think, but then previous yes/no answers are no longer so cut and dry.

    Are you a male?

    • (Score: 1, Funny) by Anonymous Coward on Monday November 05 2018, @07:08PM (1 child)

      by Anonymous Coward on Monday November 05 2018, @07:08PM (#758135)

      I'm an Anonymous Coward striving for (and apparently failing to acquire) a +1 Funny. Perhaps data management and mathematics jokes aren't as universally accessible as I'd thought.

      • (Score: 3, Touché) by c0lo on Monday November 05 2018, @11:32PM

        by c0lo (156) Subscriber Badge on Monday November 05 2018, @11:32PM (#758263) Journal

        Perhaps data management and mathematics jokes aren't as universally accessible as I'd thought.

        The process of growing up takes quite a long time in males.
        I'm happy (for you) to see you haven't stopped on the way.

        --
        https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
  • (Score: 2) by Pino P on Monday November 05 2018, @05:59PM

    by Pino P (4721) on Monday November 05 2018, @05:59PM (#758084) Journal

    0 people growing inside a fertile woman: Not pregnant
    1 person growing inside a fertile woman: Pregnant
    2 people growing inside a fertile woman: More pregnant, in this case with twins